The present invention relates to a circuit for limiting temperature without distortion in audio power amplifiers.
As is known, monolithically integrated audio amplifiers are normally protected against excessive temperatures (higher than 150.degree. C.) by an appropriately configured circuit. This circuit, which can consist only of a transistor in the simplest case, limits the current in the final stage when said temperature is exceeded, for example by switching off some current sources provided in said stage, thus limiting the dissipated power. In this manner the audio amplifier/heat dissipator system, which is normally associated in integrated circuits, self limits its power so as to keep the temperature in the integrated circuit (average temperature of the silicon chip) around the maximum design value (generally equal to 150.degree. C.).
This kind of limitation, however, is disadvantageous, since switching off some of the components of the amplifier causes distortion in the waveform of the output signal, thus negatively affecting fidelity in reproduction.
This solution is therefore unacceptable for certain applications.